Method for producing 1,3-butylene glycol, and 1,3-butylene glycol product

ABSTRACT

Provided is a method capable of yielding high-purity 1,3-butylene glycol having a very low content of a high boiling point component and a low dry point, with a high recovery ratio. A method for producing 1,3-butylene glycol to yield purified 1,3-butylene glycol from a reaction crude liquid containing 1,3-butylene glycol,in which, in a high boiling point component removal column for use in the removing a high boiling point component, a charged liquid containing 1,3 -butylene glycol is distilled under conditions that (i) a reflux ratio is greater than 0.02 in a case where a concentration of 1,3-butylene glycol in the charged liquid is 95% or less, or a reflux ratio is greater than 0.01 in a case where the concentration of 1,3-butylene glycol in the charged liquid is greater than 95%, and (ii) a bottom ratio of less than 30 wt. %, high-purity 1,3-butylene glycol is distilled off from above a charging plate, and a liquid in which a high boiling point component is concentrated is extracted from below the charging plate.

TECHNICAL FIELD

The present disclosure relates to a method for producing 1,3-butylene glycol, and a 1,3-butylene glycol product. The present application claims priority from the Japanese Patent Application No. 2019-239974, the Japanese Patent Application No. 2019-239975, the Japanese Patent Application No. 2019-239976, the Japanese Patent Application No. 2019-239977, the Japanese Patent Application No. 2019-239978, the Japanese Patent Application No. 2019-239979 filed in Japan on Dec. 28, 2019, the Japanese Patent Application No. 2020-006660 filed in Japan on Jan. 20, 2020, and the Japanese Patent Application No. 2020-018910 filed in Japan on Feb. 6, 2020, the contents of which are incorporated herein by reference.

BACKGROUND ART

1,3-Butylene glycol is a colorless, transparent, and odorless liquid and has properties, such as low volatility, low toxicity, and high hygroscopicity, and has excellent chemical stability. 1,3-butylene glycol has a wide range of applications, including raw materials for various synthetic resins and surfactants, as well as materials for cosmetics, hygroscopic agents, high boiling point solvents, and antifreezes, etc. Particularly in recent years, 1,3-butylene glycol has been attracting attention for having excellent properties as a moisturizer, and demand is growing in the cosmetic industry.

A reaction crude liquid during production of 1,3-butylene glycol contains a large number of low boiling point impurities such as ethanol, butanol, acetaldehyde, crotonaldehyde, and esters. Dimerization or polymerization to a higher degree of acetaldehyde, crotonaldehyde, and the like, among them, form high boiling point impurities. In addition, even in purification of 1,3-butylene glycol, low boiling point impurities and high boiling point impurities are produced by heat or the like. In products of 1,3-butylene glycol, less impurities are desirable. JP 06-329664 A discloses a method of controlling an impurity derived from crotonaldehyde, which is a low boiling point impurity. JP 2001-213828 A discloses a high-yield, economically advantageous production of a high-purity 1,3-butylene glycol product in which a reaction crude liquid of 1,3-butylene glycol synthesized by hydrogenation of acetaldols is made basic, followed by distillation of an alcohol, and then this liquid is distilled. Furthermore, this document describes distilling off ethanol, isopropyl alcohol, and butanol as low boiling point impurities by distillation.

CITATION LIST Patent Document

Patent Document 1: JP 06-329664 A

Patent Document 2: JP 2001-213828 A

SUMMARY OF INVENTION Technical Problem

However, with the known methods, a low boiling point component and a high boiling point component are not sufficiently removed from 1,3 butylene glycol. Cosmetics, which are an important application of 1,3 butylene glycol, typically contain water and require a long period of time from production to actual use by general consumers. In addition, from the viewpoint, such as storage stability of cosmetics, liquidity is strictly controlled.

When 1,3-butylene glycol containing a low boiling point component and a high boiling point component is used in cosmetics, an acid concentration increase can disrupt the liquidity balance of the cosmetics, and this can lead to a loss of the intended effect. In addition, the acid concentration increase of cosmetics can cause rough skin or the like of the users.

Further, during use and/or storage after use of a cosmetic, the cosmetic is exposed to air. In addition, in manufacturing cosmetics, the manufacturing work is usually performed in air atmosphere, and the product may be heated for the purposes of, for example, sterilization. When 1,3-butylene glycol containing a low boiling point component and a high boiling point component is used in cosmetics, sometimes coloration occurs in the presence of air or by effects of heating.

To solve such problems, removing by-products from crude 1,3-butylene glycol to obtain high-purity 1,3-butylene glycol has been required.

On the other hand, one of quality standards for 1,3-butylene glycol is dry point. The lower the dry point, the better the quality. When the high boiling point impurities produced in the reaction and the purification processes are mixed into products, not only their purity is reduced, but also the dry point increases, resulting in a problem that the products do not meet the product quality standards. However, a method of separation and removal of high boiling point impurities has hardly been studied so far.

Therefore, an object of the present disclosure is to provide a method capable of producing high-purity 1,3-butylene glycol having a very low content of a high boiling point component and a low dry point, with a high recovery ratio.

Another object of the present disclosure are to provide a high-purity 1,3-butylene glycol product having a very low content of a high boiling point component and a low dry point.

Still another object of the present disclosure is to provide a moisturizer and a cosmetic product that have an excellent moisturizing performance and can retain high quality for a long period of time.

Solution to Problem

As a result of diligent research to achieve the above-described purpose, the inventors of the present disclosure have found that, when a reflux ratio and a bottom ratio of a distillation column for removal of a high boiling point component are controlled, a high boiling component is concentrated and removed from below a charging plate of the high boiling point component removal column, and 1,3-butylene glycol which has a reduced high boiling component concentration is extracted from above the charging plate of the high boiling point component removal column. Thus, three effects of: reducing a high boiling point impurity concentration of a product to improve the purity; controlling a dry point within a standard value; and maintaining or improving the recovery ratio of 1,3-butylene glycol, can be attained at the same time. The present disclosure was completed based on these findings.

Specifically, the present disclosure provides a method for producing 1,3-butylene glycol to yield purified 1,3-butylene glycol from a reaction crude liquid containing 1,3-butylene glycol,

the method including: performing dehydration for removing water by distillation, removing a high boiling point component including removing a high boiling point component by distillation, and performing product distillation to yield purified 1,3-butylene glycol,

wherein, in a high boiling point component removal column for use in the removing the high boiling point component, a charged liquid including 1,3-butylene glycol is distilled under a condition that a reflux ratio is greater than 0.02 in a case where a concentration of 1,3-butylene glycol in the charged liquid is 95% or less, or a reflux ratio is greater than 0.01 in a case where the concentration of 1,3-butylene glycol in the charged liquid is greater than 95%, and high-purity 1,3-butylene glycol is distilled off from above a charging plate, and a liquid in which a high boiling point component is concentrated is extracted from below the charging plate.

The reaction crude liquid containing 1,3-butylene glycol may be a reaction crude liquid formed by hydrogen reduction of acetaldols.

The producing method further includes alkaline treatment including treating a process stream containing 1,3-butylene glycol with a base.

The producing method may further include desalting including removing a salt in a process stream containing 1,3-butylene glycol.

The producing method may further include performing dealcoholization (low boiling point component removal) including removing a low boiling point component including an alcohol, the low boiling point component being in the process stream containing 1,3-butylene glycol.

The reflux ratio of the high boiling point component removal column may be greater than 0.02.

The concentration of 1,3-butylene glycol in the charged liquid into the high boiling point component removal column may be 95% or greater.

A content of the high boiling point component in the charged liquid into the high boiling point component removal column may be 4% or less.

The content of the high boiling point component in the charged liquid into the high boiling point component removal column may be 0.1% or less.

A bottom ratio in the high boiling point component removal column may be less than 30 wt. %.

The bottom ratio in the high boiling point component removal column may be 0.01 wt. % or greater.

A theoretical number of plates in the high boiling point component removal columns is, for example, from 1 to 100 plates.

At least a portion of a bottom from the high boiling point component removal column may be recycled to the step prior to the removing a high boiling point component.

A recycled amount of the bottom from the high boiling point component removal column recycled to the step prior to the removing a high boiling point component may be less than 30 wt. % with respect to a charged amount into the high boiling point component removal column, in a range not greater than an amount of the bottom from the high boiling point component removal column.

A recycled amount of the bottom from the high boiling point component removal column recycled to the step prior to the removing a high boiling point component may be 0.01 wt. % or greater with respect to the charged amount into the high boiling point component removal column, in a range of not greater than an amount of the bottom from the high boiling point component removal column.

The present disclosure also provides a 1,3-butylene glycol product, having a dry point of 209° C. or lower and, according to a gas chromatographic analysis performed under conditions set forth below:

an area ratio of a 1,3-butylene glycol peak of greater than 98.5% and a total area ratio of peaks longer in retention time than the 1,3-butylene glycol peak of less than 1.2%,

in which the conditions for the gas chromatographic analysis are as follows:

Analytical Column: a column with dimethylpolysiloxane as a stationary phase, having a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 1.0 μm

Heating conditions: heating from 80° C. to 120° C. at 5° C./min, then heating again to 160° C. at 2° C./min and maintaining for 2 minutes, and further heating to 230° C. at 10° C./min and maintaining at 230° C. for 18 minutes

Sample Introduction Temperature: 250° C.

Carrier Gas: helium

Column Gas Flow Rate: 1 mL/min

Detector and Detection Temperature: a flame ionization detector (FID), 280° C.

The area ratio of the 1,3-butylene glycol peak may be 99.0% or greater.

The total area ratio of the peaks longer in retention time than the 1,3-butylene glycol peak may be 0.6% or less.

The present disclosure further provides a moisturizer containing the 1,3-butylene glycol product described above.

The present disclosure further provides a cosmetic product containing the moisturizer described above.

In the present disclosure, “1,3-butylene glycol product” means a composition in which 1,3-butylene glycol accounts for a majority among the components (e.g., a 1,3-butylene glycol content is 95 wt. % or greater, preferably 98 wt. % or greater).

Advantageous Effects of Invention

According to the producing method of the present disclosure, it is possible to produce high-purity 1,3-butylene glycol having a very low content of a high boiling point component and a low dry point, with a high recovery ratio.

In addition, the 1,3-butylene glycol product of the present disclosure has a very low content of a high boiling point component, a low dry point, and high purity. Therefore, it is suitably used as a moisturizer and in an application as a raw material for cosmetics.

Further, the moisturizer and cosmetic product of the present disclosure are excellent in moisturizing performance and have an extremely low content of a high boiling point component, and thus can maintain high quality for a long period of time.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a flowchart illustrating a producing method (purification method) for a 1,3-butylene glycol product of the present disclosure.

FIG. 2 is a chromatogram showing a chart for gas chromatographic analysis of a 1,3-butylene glycol product in Example 10.

FIG. 3 is a chromatogram showing a chart for gas chromatographic analysis of a 1,3-butylene glycol product in Comparative Example 2.

DESCRIPTION OF EMBODIMENTS

[Method for Producing 1,3-butylene Glycol]

The method for producing 1,3-butylene glycol of the present disclosure is a method for producing 1,3-butylene glycol to yield purified 1,3-butylene glycol from a reaction crude liquid containing 1,3-butylene glycol (1,3 BG) (hereinafter sometimes referred to as “crude 1,3-butylene glycol”), the method including: performing dehydration including removing water by distillation, removing high boiling point component including removing a high boiling point component by distillation, and performing product distillation to yield purified 1,3-butylene glycol. In a high boiling point component removal column for use in the removing a high boiling point component, a charged liquid containing 1,3-butylene glycol is distilled under a condition that a reflux ratio is greater than 0.02 in a case where a concentration of 1,3-butylene glycol in the charged liquid is 95% or less, or a reflux ratio is greater than 0.01 in a case where the concentration of 1,3-butylene glycol in the charged liquid is greater than 95%, high-purity 1,3-butylene glycol is distilled off from above a charging plate, and a liquid in which a high boiling point component is concentrated is extracted from below the charging plate.

[Crude 1,3-butylene Glycol]

Examples of the crude 1,3-butylene glycol include (1) a reaction crude liquid produced by reduction (hydrogenation) of acetaldols, (2) a reaction crude liquid produced by hydrolysis of 1,3-butylene oxide, (3) a reaction crude liquid produced by selective hydrocracking of erythritol, (4) a reaction crude liquid produced by selective hydration to butadiene, (5) a reaction crude liquid produced by hydrogen addition to n-butanal-3-one, (6) a reaction crude liquid produced by hydrogen addition to 1-butanol-3-one, (7) a reaction crude liquid produced by hydrogen addition to 3-hydroxy-l-butanoic acid, (8) a reaction crude liquid produced by hydrogen addition to β-butyrolactone, and (9) a reaction crude liquid produced by hydrogen addition to diketene. In the present disclosure, the crude 1,3-butylene glycol may be one type or a mixture of two or more types of the above (1) to (9). The crude 1,3-butylene glycol is preferably (1) the reaction crude liquid produced by reduction (in particular, liquid phase reduction) of acetaldols.

Hereinafter, a case where the reaction crude liquid produced by reduction (hydrogenation) of acetaldols is used as the crude 1,3-butylene glycol will be mainly described. Note that the reduction (hydrogenation) of acetaldols is sometimes referred to as “hydrogenation”.

The acetaldols used as a raw material in the hydrogenation is not particularly limited as long as it is a compound that is converted to 1,3-butylene glycol by hydrogen reduction. Examples of the raw material acetaldols include acetaldol; its cyclic dimer paraldol; aldoxane as a cyclic trimer of acetaldehyde; and mixtures of these.

The method of manufacturing the acetaldols (e.g., acetaldol or paraldol) is not particularly limited, but the acetaldols may be, for example, those produced by an aldol condensation reaction of acetaldehyde in the presence of a basic catalyst or those produced by pyrolysis or the like of aldoxane. Note that the production of the acetaldols is sometimes referred to as “acetaldol production” or “acetaldehyde polymerization”.

A reaction crude liquid produced by the reaction described above and containing acetaldols may be neutralized with an acid and used in the manufacturing of 1,3-butylene glycol. Such a reaction crude liquid may contain, in addition to acetaldols, acetaldehyde (AD), crotonaldehyde (CR), another aldehyde component; a low boiling point substance; a high boiling point substance, such as an aldehyde dimer or trimer; water; a salt; and the like. In the present specification, a compound with a lower boiling point than that of 1,3-butylene glycol may be referred to as a “low boiling point substance” or “low boiling substance”, and a compound with a higher boiling point than that of 1,3-butylene glycol may be referred to as a “high boiling point sub stance” or “high boiling substance”.

The reaction crude liquid containing acetaldols may be subjected to a pretreatment, such as dealcoholization distillation, dehydration distillation, desalting, alkaline treatment and dealkalization treatment, or impurity removal, as necessary, and a liquid produced by removing by-products, such as unreacted acetaldehyde and crotonaldehyde, may be used. Examples of the pretreatment method include distillation, adsorption, ion exchange, conversion to a high boiling point substance by heating, and decomposition. For the distillation, a distillation method of various types, such as reduced pressure, normal pressure, increased pressure, azeotropic, extraction, or reaction, can be used. In particular, it is preferred that the reaction crude liquid containing acetaldols is subjected to simple evaporation, distillation, or hydrogen addition to remove aldehydes such as acetaldehyde and crotonaldehyde, followed by the hydrogenation.

The content of the acetaldols in the raw material for hydrogenation is not particularly limited but is, for example, preferably 30 wt. % or greater (e.g., from 30 to 99 wt. %), more preferably 40 wt. % or greater (for example, from 40 to 98 wt. %), 50 wt. % or greater (for example, from 50 to 97 wt. %) or 60 wt. % or greater (for example, from 60 to 95 wt. %), and even more preferably from 65 to 90 wt. %, particularly preferably from 70 to 90 wt. %, and most preferably from 75 to 90 wt. %. With the content of the acetaldols within the above ranges, impurities contained in the reaction crude liquid containing 1,3-butylene glycol (crude 1,3-butylene glycol) tend to be reduced.

The raw material for hydrogenation may or may not contain water but preferably contains water from the viewpoint of the purity of 1,3-butylene glycol product. The water content in the raw material for hydrogenation is not particularly limited but is, for example, preferably 2 wt. % or greater, more preferably 5 wt. % or greater, even more preferably 10 wt. % or greater, and particularly preferably 15 wt. % or greater. The upper limit may be, for example, 90 wt. %, 80 wt. %, 70 wt. %, 60 wt. %, 50 wt. %, 40 wt. %, 30 wt. % or 20 wt. %. With the water content within the above ranges, the acetal of 1,3-butylene glycol and acetaldol contained in the resulting crude 1,3-butylene glycol is reduced, and thus this tends to increase the purity of the 1,3-butylene glycol product finally produced. This is because the raw material for hydrogenation contains water to a certain extent, and the acetal is hydrolyzed into 1,3-butylene glycol accordingly as well as coexisting acetaldol is reduced into 1,3-butylene glycol.

Examples of the hydrogenation catalyst include Raney nickel. The hydrogenation catalyst can also be used in a suspended state, and can also be filled in a reaction vessel and used. The amount of the hydrogenation catalyst to be used is not particularly limited but is, for example, preferably from 1 to 30 parts by weight, more preferably from 4 to 25 parts by weight, even more preferably from 8 to 20 parts by weight, and particularly preferably from 12 to 18 parts by weight relative to 100 parts by weight of the raw material for hydrogenation. The amount of hydrogen to be used in the reduction reaction is not particularly limited but is, for example, preferably from 0.5 to 40 parts by weight, more preferably from 1 to 30 parts by weight, even more preferably from 4 to 20 parts by weight, and particularly preferably from 8 to 12 parts by weight relative to 100 parts by weight of the raw material for hydrogenation. A pressure (total pressure; gauge pressure) in a reaction system in the reduction reaction is not particularly limited but is, for example, preferably from 9 to 70 MPa and more preferably from 10 to 40 MPa. A hydrogen pressure (partial pressure of hydrogen) in the reaction system is not particularly limited, but is, for example, from 7 to 60 MPa, and preferably from 10 to 30 MPa. A reaction temperature in the reduction reaction is not particularly limited but is, for example, from 40 to 150° C., preferably from 50 to 140° C., and more preferably from 60 to 130° C. A reaction time (residence time) in the reduction reaction is not particularly limited but is, for example, from 10 to 500 minutes, preferably from 20 to 400 minutes, more preferably from 30 to 300 minutes, even more preferably from 50 to 280 minutes, and particularly preferably from 80 to 250 minutes. The present reaction can be carried out in any of a batch, semi-batch, or continuous manner.

For example, the thus-produced crude 1,3-butylene glycol contains a low boiling point substance (low boiling point compound) having an unsaturated bond, such as acetaldehyde (AD), butylaldehyde, crotonaldehyde (CR), acetone, and methyl vinyl ketone; a condensate of these; a condensate of 1,3-butylene glycol and the low boiling point substance above (e.g., an acetal of 1,3-butylene glycol and acetaldol); an alcohol such as ethanol, isopropyl alcohol, or butanol; water (solvent and the like), a salt produced by neutralization or the like, a catalyst (when used in suspension) or the like. Removal of these impurities in the purification can yield a 1,3-butylene glycol product (purified 1,3-butylene glycol).

[Purification of Crude 1,3-butylene Glycol]

The producing method according to the present disclosure includes, at least, performing dehydration including removing water by distillation, removing high boiling point component (high boiling point substance removal distillation) including removing a high boiling point component by distillation, and performing product distillation to yield purified 1,3-butylene glycol. The dehydration and the high boiling point component removal are both provided before the product distillation, but the order of the dehydration and the high boiling point component removal is not particularly limited. The producing method according to the present disclosure may include, in addition to these steps, desalting, alkaline reaction (alkaline treatment), and dealkalization. Additionally, prior to the dehydration, catalyst separation, neutralization by alkali, dealcoholization (low boiling point component removal), and the like can be provided. These steps may be performed in the order described above, but the order of the steps may be changed as appropriate except that the dealkalization is provided after the alkaline reaction. For example, the dealcoholization (low boiling point component removal), the desalting, the alkaline reaction, and the dealkalization can be provided at appropriate points, but are usually provided after the hydrogenation. Note that, among the steps described above, the catalyst separation, the neutralization by alkali, the dealcoholization (low boiling point component removal), the desalting, the alkaline reaction, and the dealkalization may be provided as necessary, and do not necessarily have to be provided.

FIG. 1 is a flow sheet of an apparatus illustrating an example of an embodiment of a method for producing 1,3-butylene glycol according to the present disclosure. A is a dehydration column and is related to the dehydration. B is a desalting column and is related to the desalting. C is a distillation column for removing a high boiling point substance (high boiling point component removal column) and is related to the distillation for removal of a high boiling point substance (high boiling point component removal). D is an alkaline reactor and is related to the alkaline reaction. E is a dealkalization column and is related to the dealkalization. F is a product distillation column (product column) and is related to the product distillation. A-1, B-1, C-1, E-1, and F-1 are condensers. A-2, C-2, and F-2 are reboilers. Hereinafter, an example of an embodiment of a method for producing 1,3-butylene glycol according to the present disclosure will be described using the present flow sheet.

Crude 1,3-butylene glycol (corresponding to “X-1”) produced by hydrogen reduction of a raw material for hydrogenation is fed to the dehydration column A. In the dehydration column A, water is distilled off from the top of the column by distillation, and from the bottom of the column, a crude 1,3-butylene glycol stream containing 1,3-butylene glycol is produced. Note that the crude 1,3-butylene glycol (corresponding to “X-1”) may undergo the dealcoholization (distillation by a dealcoholization column) for removal of an alcohol such as ethanol and a low boiling point substance, and then may be supplied to the dehydration column A.

The crude 1,3-butylene glycol stream is fed to the desalting column B. In the desalting column B, the crude 1,3-butylene glycol stream after the desalting is produced from the top of the column, and a salt, a high boiling point substance, or the like is discharged from the bottom of the column. The bottom ratio (%) of the desalting column B [(desalting column bottom amount (part)/desalting column charge amount (part)×100] is, for example, from 0.1 to 40 wt. %, preferably from 1 to 35 wt. %, more preferably from 2 to 30 wt. %, even more preferably from 3 to 25 wt. %, and particularly preferably from 5 to 20 wt. %, and may be from 7 to 15 wt. %. At least a portion of the bottom in the desalting column may be recycled to the step prior to the desalting.

The crude 1,3-butylene glycol stream after the desalting described above is fed to the high boiling point component removal column C. In the high boiling point component removal column C, a high boiling point component (also referred to as high boiling point substance) is discharged from below the charging plate (preferably from the bottom of the column). On the other hand, the crude 1,3-butylene glycol stream after high boiling point substance removal (high-purity 1,3-butylene glycol) is produced from above the charging plate.

The high boiling point component removal column C can be, for example, a perforated-plate column, a bubble column, or the like, but is more preferably a packed column with a low pressure loss, filled with Sulzer Packing, Melapack (both are trade names of Sumitomo Heavy Industries, Ltd.). This is because 1,3-butylene glycol and trace impurities would be thermally decomposed at a high temperature (e.g., 150° C. or higher) and produce a low boiling point substance, which is a coloring component, and thus the distillation temperature is to be lowered. In addition, this is also because a long thermal history (residence time) for 1,3-butylene glycol would also have a similar effect. Thus, the reboiler employed is preferably one with a short residence time of the process side fluid, for example, a thin-film evaporator, such as a natural downward flow thin-film evaporator or a forced-stirring thin-film evaporator.

A theoretical number of plates of the high boiling point component removal column C is, for example, from 1 to 100 plates, preferably from 2 to 90 plates, more preferably from 3 to 80 plates, more preferably from 4 to 70 plates, from 5 to 60 plates, from 8 to 50 plates, or from 10 to 40 plates, and particularly preferably from 15 to 30 plates. A feed position for the charged liquid is, for example, from 10 to 90%, preferably from 20 to 80%, and more preferably from 30 to 70 plates, and even more preferably from 40 to 60% of a height of the column downward from the top of the high boiling point component removal column. In the distillation in the high boiling point component removal column C, a pressure (absolute pressure) at the top of the column is, for example, from 0.01 to 50 kPa, preferably from 0.1 to 30 kPa, more preferably from 0.3 to 20 kPa, and even more preferably from 0.5 to 10 kPa.

A concentration of 1,3 BG in the charged liquid into the high boiling point component removal column C is, for example, 95% or greater, preferably 96% or greater, more preferably 97% or greater, even more preferably 98% or greater, and particularly preferably 99% or greater. The concentration of 1,3 BG in the charged liquid into the high boiling point component removal column C can be improved by adjustment of the distillation conditions of the dehydration column A and the desalting column B. For example, increasing the reflux ratio of the dehydration column A or increasing the bottom ratio of the desalting column B can increase the concentration of 1,3 BG in the charged liquid into the high boiling point component removal column C. Note that the concentration of the 1,3 BG described above is an area proportion (area %) of a 1, 3 BG peak relative to a total peak area in a gas chromatographic analysis (GC analysis) under the following conditions.

in which the conditions for the gas chromatographic analysis are as follows:

Analytical Column: a column with dimethylpolysiloxane as a stationary phase, having a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 1.0 μm

Heating conditions: heating from 80° C. to 120° C. at 5° C./min, then heating again to 160° C. at 2° C./min and maintaining for 2 minutes, and further heating to 230° C. at 10° C./min and maintaining at 230° C. for 18 minutes

Sample Introduction Temperature: 250° C.

Carrier Gas: helium

Column Gas Flow Rate: 1 mL/min

Detector and Detection Temperature: a flame ionization detector (FID), 280° C.

A content of the high boiling point component in the charged liquid into the high boiling point component removal column C is, for example, 4% or less, preferably 3% or less, more preferably 2% or less, even more preferably 1% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, 0.1% or less, or 0.05% or less, and particularly preferably 0.01% or less. The content of the high boiling point component in the charged liquid into the high boiling point component removal column C can be reduced by adjustment of the distillation conditions of the desalting column B. For example, increasing the bottom ratio of the desalting column B can reduce the content of the high boiling point component in the charged liquid into the high boiling point component removal column C. Note that the content of the high boiling point component in the charged liquid into the high boiling point component removal column C is a total area proportion (area %) of peaks longer in retention time than the 1,3 BG peaks relative to the total peak area in the gas chromatographic analysis under the above conditions.

In the producing method according to the present disclosure, the reflux ratio in the high boiling point component removal column C [high boiling point component removal column reflux amount/high boiling point component removal column distilled amount (discharge amount to outside of distillation column)] is greater than 0.02 (e.g., 0.025 or greater) when the concentration of 1,3 BG in the charged liquid into the high boiling point component removal column C is less than 95%, and is greater than 0.01 (e.g., 0.015 or greater) when the concentration of 1,3 BG in the high boiling point component removal column C is 95% or greater. From the perspective of lowering the dry point of 1,3-butylene glycol product, the reflux ratio is preferably greater than 0.02 (e.g., 0.05 or greater), more preferably 0.1 or greater, more preferably 0.2 or greater, 0.3 or greater, 0.4 or greater, 0.5 or greater, 0.6 or greater, 0.7 or greater, 0.8 or greater, 0.9 or greater, 1 or greater, 1.2 or greater, 1.5 or greater, 2 or greater, 3 or greater, 4 or greater, 5 or greater, or 10 or greater, and particularly preferably 20 or greater. Note that an upper limit of the reflux ratio is, for example, 100, preferably 50, from the perspective of energy costs.

In the producing method according to the present disclosure, the reflux ratio in the high boiling point component removal column C is within the specified range described above, and thus high-purity 1,3 BG having a very low content of a high boiling point component and a low dry point can be produced with a high recovery ratio.

In the producing method according to the present disclosure, the bottom ratio of the high boiling point component removal column C is, for example, less than 30 wt. %. It should be noted that the bottom ratio is not limited to this value when the bottom of the high boiling point component removal column is distilled in a further distillation column and subjected to high boiling point component removal and 1,3 BG after this process is made a product. When an amount ratio of the final high boiling point component-containing product extracted to the outside of the system is reduced to less than 30 wt. % with respect to the charged amount into the high boiling point component removal column C, it is possible to obtain 1,3 BG in a high yield. Note that the bottom ratio refers to a proportion (wt. %) of an amount of liquid extracted from below the charging plate (for example, bottom of the column) of the high boiling point component removal column C relative to the charged amount into the high boiling point component removal column C (also including a recycled amount of the liquid, when the liquid is recycled to the previous steps which will be described later). Note that when the liquid is recycled to the previous steps described below, the recovery ratio of 1,3 BG is improved as the discharge ratio to the outside is smaller.

From the perspective of improving the recovery ratio of 1,3 BG, the bottom ratio of the high boiling point component removal column C can also be preferably 25 wt. % or less, more preferably 20 wt. % or less, even more preferably 15 wt. % or less, 10 wt. % or less, 7 wt. % or less, 5 wt. % or less, 4 wt. % or less, 3 wt. % or less, or 2 wt. % or less, and can be 1 wt. % or less. In addition, from the perspective of lowering the dry point of the 1,3-butylene glycol product, the bottom ratio of the high boiling point component removal column is, for example, 0.01 wt. % or greater, preferably 0.1 wt. % or greater, 0.5 wt. % or greater, or 1 wt. % or greater, more preferably 2 wt. % or greater, 3 wt. % or greater, 4 wt. % or greater, 5 wt. % or greater, 6 wt. % or greater, 7 wt. % or greater, 8 wt. % or greater, 9 wt. % or greater, 10 wt. % or greater, or 15 wt. % or greater, and particularly preferably 20 wt. % or greater.

At least a portion of the liquid that has been yielded by concentrating the high boiling component extracted from below the charging plate of the high boiling point component removal column C (hereinafter, sometimes referred to as “bottom”) may be recycled to step prior to the high boiling point component removal (dashed arrow illustrated in the lower part of the high boiling point component removal column C in FIG. 1 ). The recovery ratio of 1,3 BG can be improved by recycling at least a portion of the bottom to the step prior to the high boiling point component removal. Note that, in the present specification, the recovery ratio of 1,3 BG in the high boiling point component removal column C is a value (%) determined by the following formula.

{1−[GC area % of 1,3 BG in bottom]×(bottom amount(part)−recycled amount(part)of bottom]/(GC area % of 1,3 BG in charged liquid×charged amount (part)}×100

Note that the low boiling point substance and the high boiling point substance may be hydrolyzed by water to produce 1,3 BG, while the high boiling point substance may be produced by polymerization of 1,3 BG. Further, due to the formation or disappearance of trace impurities, the mass balance in the high boiling point component removal column may not always be ensured. This applies to the dealcoholization column (low boiling point component removal column), the dehydration column, the product column, and other distillation columns.

Examples of the step prior to the removing a high boiling point component include acetaldehyde polymerization (aldol condensation of acetaldehyde), reaction (hydrogenation), dealcoholization (low boiling point component removal), dehydration, and desalting. Among these steps, the bottom is preferably recycled to the acetaldehyde polymerization (aldol condensation of acetaldehyde), since 1,3 BG is produced by hydrolysis of the high boiling point substance. In addition, the hydrogen addition reduction may produce 1,3 BG, and the bottom may be recycled to the hydrogen addition from that viewpoint.

The recycled amount of the bottom recycled to the step prior to the removing a high boiling point component can be appropriately selected within a range of the amount of the bottom. The recycled amount of the bottom recycled to the step prior to the removing a high boiling point component is, for example, less than 30 wt. %, preferably 25 wt. % or less with respect to the charged amount into the high boiling point component removal column C. Note that the recycled amount of the bottom recycled may be 20 wt. % or less, 15 wt. % or less, 10 wt. % or less, 7 wt. % or less, 5 wt. % or less, 4 wt. % or less, 3 wt. % or less, 2 wt. % or less, or 1 wt. % or less with respect to the charged amount into the high boiling point component removal column C. In addition, from the perspective of improving the recovery ratio of 1,3 BG in the high boiling point component removal column and the yield of 1,3 BG throughout the 1,3 BG producing process, the recycled amount of the bottom recycled to the steps before the removing a high boiling point component is, for example, 0.01 wt. % or greater, preferably 0.1 wt. % or greater, more preferably 2 wt. % or greater, 3 wt. % or greater, 4 wt. % or greater, 5 wt. % or greater, 7 wt. % or greater, or 10 wt. % or greater, and particularly preferably 20 wt. % or greater with respect to the charged amount into the high boiling point component removal column C. Note that, in a case where the amount of the bottom is reduced to the minimum, 1,3 BG can be recovered in a high yield, even without being recycled to the previous steps.

The crude 1,3-butylene glycol stream taken out from above the charging plate of the high boiling point component removal column C is fed to the alkaline reactor (e.g., a flow-through tubular reactor) D and is treated with a base (treated with alkali). The base treatment can decompose by-products contained in the crude 1,3-butylene glycol. The base is added to the alkaline reactor D or its upstream piping or the like. The base is added in an amount of, for example, from 0.05 to 10 wt. %, preferably from 0.1 to 1.0 wt. % relative to the crude 1,3-butylene glycol stream subjected to the alkaline treatment. With the added amount of the base exceeding 10 wt. %, the base would precipitate in the distillation column, piping, or the like, and this may cause blockage. In addition, the decomposition reaction of a high boiling point compound would occur, and by-products may be produced adversely. With the added amount of the base of less than 0.05 wt. %, the effect of decomposing by-products is reduced.

The base added in the alkaline reactor D or its upstream piping is not particularly limited but is, for example, preferably an alkali metal compound. Examples of the alkali metal compound include sodium hydroxide, potassium hydroxide, sodium (bi)carbonate, and potassium (bi)carbonate. A basic ion exchange resin can also be used as the base. The base is preferably sodium hydroxide or potassium hydroxide from the perspective of reducing the byproducts contained in the 1,3-butylene glycol product produced finally. The base may be added as is in the solid form but is preferably added in an aqueous solution to facilitate operation and contact with a solution to be treated. One of the bases described above may be used alone, or two or more may be used simultaneously.

The reaction temperature in the alkaline reactor D is not particularly limited but is, for example, preferably from 90 to 140° C. and more preferably from 110 to 130° C. The reaction at a reaction temperature lower than 90° C. would require long reaction residence time and thus require a reactor with a large volume and make the process uneconomical. The reaction at a reaction temperature exceeding 140° C. would increase coloration in the 1,3-butylene glycol product produced finally. The reaction residence time is, for example, preferably from 5 to 120 minutes and more preferably from 10 to 30 minutes. A reaction residence time shorter than 5 minutes may cause an insufficient reaction and adversely affect the quality of the 1,3-butylene glycol product produced finally. A reaction residence time exceeding 120 minutes would require a large reactor and increase the cost of equipment, and thus would be disadvantageous from the economic point of view.

After exiting the alkaline reactor D, the reaction crude liquid stream is fed to the dealkalization column (e.g., thin film evaporator) E if necessary, and the base and the like are removed from the bottom of the column by evaporation. On the other hand, from the top of the dealkalization column E, a crude 1,3-butylene glycol stream after the removal of a base is yielded. The evaporator used for the dealkalization column E is suitably a natural downward flow thin-film evaporator or a forced-stirring thin-film evaporator with a short residence time for the purpose of reducing the thermal history to the process fluid. A demister may be installed in a space above the charging position of the dealkalization column (e.g., thin film evaporator) E, and droplets of a base or the like may be removed. This makes it possible to prevent the base and the high boiling point substance from being mixed into the 1,3-butylene glycol product.

Evaporation is performed in the evaporator used for the dealkalization column E, for example, under a reduced pressure at the top of the column of 20 kPa or less (absolute pressure), preferably from 0.5 to 10 kPa (absolute pressure). The temperature of the evaporator is, for example, preferably from 90 to 120° C. The crude 1,3-butylene glycol stream containing a low boiling point substance distilled from the top of the column is fed to the product distillation column F.

Note that the alkaline reactor D and the dealkalization column E may be installed between the desalting column B and the high boiling point component removal column C, between the dehydration column A and the desalting column B (in this case, the desalting column may also serve as a dealkalization column), or before the dehydration column A. In addition, without providing the alkaline reactor D or the dealkalization column E, the alkaline treatment can be performed by charging the base into a high boiling point component removal column charging line or into a dehydration column charging line, or adding the base to the reaction solution after the hydrogenation [and then charging the base into the dealcoholization column (low boiling point component removal column)].

The product distillation column F can be, for example, a perforated-plate column, a bubble column, or the like, but is more preferably a packed column with a low pressure loss, filled with Sulzer Packing, Melapack (trade names of Sumitomo Heavy Industries, Ltd.). This is because 1,3-butylene glycol and trace impurities would be thermally decomposed at a high temperature (e.g., 150° C. or higher) and form a low boiling point substance, which is a coloring component. Thus, the distillation temperature is to be lowered. In addition, this is also because a long thermal history (residence time) for 1,3-butylene glycol would also have a similar effect. Thus, the reboiler employed is preferably one with a short residence time of the process side fluid, for example, a thin-film evaporator, such as a natural downward flow thin-film evaporator or a forced-stirring thin-film evaporator.

A theoretical number of plates of the product distillation column F is, in a case where the concentration of the low boiling point substance in the charged liquid is 5 wt. % or less, for example, from 1 to 100 plates, preferably from 2 to 90 plates, from 3 to 80 plates, from 4 to 70 plates, or from 5 to 60 plates, from 8 to 50 plates, or from 10 to 40 plates, and more preferably from 15 to 30 plates. A feed position for the charged liquid is, for example, from 10 to 90%, preferably from 20 to 80%, and more preferably from 30 to 70%, and even more preferably from 40 to 60% of the height of the column downward from the top of the column. In the distillation in the product distillation column F, a pressure (absolute pressure) at the top of the column is, for example, from 20 kPa or less, preferably from 0.1 to 10 kPa, more preferably from 0.3 to 8 kPa, even more preferably from 0.5 to 5 kPa. The reflux ratio in the product distillation column F is, for example, from 0.05 to 500, preferably from 0.1 to 300, more preferably from 0.2 to 200, more preferably from 0.5 to 100, from 1 to 50, from 2 to 40, or from 3 to 30, and particularly preferably from 4 to 25.

In FIG. 1 , in charging to the product distillation column F, the column top vapor from the dealkalization column E is condensed in the condenser E-1, and the resulting condensed liquid is fed, but the column top vapor from the dealkalization column E may be directly fed to the product distillation column F. In the product distillation column F, an impurity, such as a low boiling point substance, is distilled off from the top of the column, and 1,3-butylene glycol as a product is produced from the bottom of the column of the product distillation column F (corresponding to “Y”).

Thus, according to the producing method of the present disclosure, it is possible to produce high-purity 1,3-butylene glycol having a very low content of a high boiling point component and a low dry point, with a high recovery ratio.

1,3-Butylene Glycol Product

The 1,3-butylene glycol product according to the present disclosure can be produced by the producing method according to the present disclosure described above. The 1,3-butylene glycol product according to the present disclosure has a dry point of 209° C. or lower and an area ratio of a 1,3-butylene glycol peak of greater than 98.5% and a total area ratio of peaks longer in retention time than the 1,3-butylene glycol peak of less than 1.2%, according to a gas chromatographic analysis (GC analysis) performed under conditions set forth below:

the conditions for the gas chromatographic analysis are as follows:

Analytical Column: a column with dimethylpolysiloxane as a stationary phase, having a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 1.0 μm

Heating conditions: heating from 80° C. to 120° C. at 5° C./min, then heating again to 160° C. at 2° C./min and maintaining for 2 minutes, and further heating to 230° C. at 10° C./min and maintaining at 230° C. for 18 minutes

Sample Introduction Temperature: 250° C.

Carrier Gas: helium

Column Gas Flow Rate: 1 mL/min

Detector and Detection Temperature: a flame ionization detector (FID), 280° C.

The area ratio of the 1,3-butylene glycol peak is preferably 98.6% or greater, 98.7% or greater, 98.8% or greater, 98.9% or greater, 99% or greater, 99.1% or greater, 99.2% or greater, or 99.3% or greater, more preferably 99.4% or greater, even more preferably 99.5% or greater or 99.6% or greater, and particularly preferably 99.7% or greater.

The total area ratio of the peaks longer in retention time than the 1,3-butylene glycol peak is preferably 1.1% or less, 1% or less, 0.9% or less, 0.8% or less, 0.7% or less, or 0.6% or less, more preferably 0.5% or less, even more preferably 0.4% or less, 0.3% or less, 0.2% or less, 0.1% or less, or 0.05% or less, and particularly preferably 0.03% or less.

In the present disclosure, the “(peak) area ratio” means an area proportion (area %) of a specific peak relative to the sum of the areas of all peaks appearing in the chromatogram. In addition, all peaks mean, for example, all of the peaks appearing in the analysis continued until and discontinued at a relative retention time of 7.8, provided that the relative retention time of 1,3-butylene glycol is 1.0.

The area ratio of the 1,3-butylene glycol peak and the total area ratio of the peaks longer in retention time than the 1,3-butylene glycol peak are within the ranges described above, and thus high-purity and high-quality 1,3-butylene glycol products are provided.

Moisturizer and Cosmetic Product

A moisturizer of the present disclosure contains the 1,3-butylene glycol product described above. Therefore, the moisturizer has excellent moisturizing performance. The moisturizer of the present disclosure may contain a component besides the 1,3-butylene glycol product described above, such as a moisturizer component besides the 1,3-butylene glycol product described above. In the moisturizer of the present disclosure, the content of the 1,3-butylene glycol product described above is, for example, 10 wt. % or greater, preferably 30 wt. % or greater, more preferably 50 wt. % or greater, even more preferably 80 wt. % or greater, and particularly preferably 90 wt. % or greater, and the moisturizer may be composed of only the 1,3-butylene glycol product described above.

A cosmetic of the present disclosure contains the moisturizer described above. The blending amount of the 1,3-butylene glycol product in the cosmetic product of the present disclosure is any amount in which the moisturizing performance can be exhibited according to the type and form of cosmetic. The blending amount of the 1,3-butylene glycol product in the cosmetic product of the present disclosure is, for example, from 0.01 to 40 wt. %, preferably from 0.1 to 30 wt. %, more preferably from 0.2 to 20 wt. %, even more preferably from 0.5 to 15 wt. %, and particularly preferably from 1 to 10 wt. %.

The cosmetic product of the present disclosure may contain, in addition to the 1,3-butylene glycol product, for example, another moisturizer; an oil, such as a vegetable oil, a hydrocarbon oil, a higher fatty acid, a higher alcohol, or a silicone; a surfactant, such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant, or a nonionic surfactant; a preservative, a sequestrant, a thickener, a powder, an ultraviolet absorber, an ultraviolet blocker, a fragrance, or a pH adjuster; or a medicinal ingredient or bioactive component, such as a vitamin preparation, a skin activator, a blood circulation promoter, a skin-lightening preparation, an antibacterial agent, or an anti-inflammatory agent.

The cosmetic product of the present disclosure can be a skin cosmetic product, such as a lotion, an emulsion, a cream, a gel, a pack, or a mask; or a hair cosmetic product, such as a shampoo, a rinse, or a hair restorer. In addition, the cosmetic product may be a sunscreen cosmetic product, a make-up cosmetic product or the like. Furthermore, the cosmetic product can be a pharmaceutical product or quasi drug containing a medical component.

The cosmetic product of the present disclosure can be produced by utilizing a method known per se.

Each aspect disclosed in the present specification can be combined with any other feature disclosed herein. Note that each of the configurations, combinations thereof, and the like in each of the embodiments are an example, and various additions, omissions, and other changes may be made as appropriate without departing from the spirit of the present disclosure. The present disclosure is not limited by the embodiments and is limited only by the claims.

EXAMPLES

Hereinafter, the present disclosure will be described more specifically with reference to examples, but the present disclosure is not limited by these examples. “Parts” used in the examples means “parts by weight” unless otherwise specified. Gas chromatographic analysis (GC analysis) and measurement of an initial boiling point were performed by the methods which will be described below.

Example 1

The method of manufacturing 1,3-butylene glycol will be described using FIG. 1 .

Relative to 100 parts of an acetaldol solution containing 30 wt. % of water (mixed solution of 70 parts of acetaldol and 30 parts of water) as a raw material, 10 parts of hydrogen were charged in a reactor for liquid-phase hydrogenation reduction, and 15 parts of Raney nickel were added as a catalyst. The reactor was kept at 120° C. and 10 MPa (gauge pressure), and liquid-phase hydrogenation reduction was performed. After the catalyst was separated, the liquid after the reaction was neutralized with sodium hydroxide, alcohols were removed, and crude 1,3-butylene glycol (1) containing a substance having a higher boiling point than that of 1,3-butylene glycol was produced.

Note that the acetaldol solution containing 30 wt. % of water, which was used as the raw material, had been produced by stirring acetaldehyde and water in the presence of 100 ppm by weight NaOH at 30° C. for a residence time of 10 hours, and dimerizing the acetaldehyde [acetaldehyde polymerization (aldol condensation of acetaldehyde)].

The crude 1,3-butylene glycol (1) (corresponding to “X-1” in FIG. 1 ) was charged in the dehydration column A. In the dehydration column A, water was extracted from the top of the column, and 15 parts of fresh water was added as reflux water relative to 100 parts of the charged liquid amount. The pressure at the top of the column was adjusted to 7 kPa (absolute pressure), and crude 1,3-butylene glycol (2) was produced from the bottom of the column, the crude 1,3-butylene glycol (2) having a total area ratio of impurity peaks shorter in retention time (RT) than 1,3-butylene glycol of 1.8% in the GC analysis which will be described later. The water extracted from the top of the column was discharged (corresponding to “X-2” in FIG. 1 ).

The crude 1,3-butylene glycol (2) was then charged in the desalting column B. In the desalting column B, a salt, a high boiling point substance, and a portion of 1,3-butylene glycol were discharged as the evaporation residue from the bottom of the column (corresponding to “X-3” in FIG. 1 ). The discharge amount of the evaporation residue was 5 parts relative to 100 parts of the charged liquid amount. On the other hand, from the top of the column, the crude 1,3-butylene glycol (3) containing 1,3-butylene glycol, a low boiling point substance, and a portion of a high boiling point substance was produced. As a result of the GC analysis of the crude 1,3-butylene glycol (3), the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 3%, and the area ratio of the 1,3-butylene glycol peak was 95%.

The crude 1,3-butylene glycol (3) was then charged in the high boiling point component removal column C. In the high boiling point component removal column C, distillation was performed under the condition of a pressure at the top of the column of 5 kPa (absolute pressure), and a high boiling point substance and a portion of 1,3-butylene glycol were discharged from the bottom of the column (corresponding to “X-4” in FIG. 1 ). The discharge amount from the bottom of the column was 20 parts relative to 100 parts of the charged liquid amount, and the discharge was incinerated as it was. On the other hand, at the top of the column, 80 parts of crude 1,3-butylene glycol (4) containing a low boiling point substance was produced, as a distillate, in a reflux ratio (reflux amount/distilled amount) of 0.05.

The crude 1,3-butylene glycol (4) was then charged in the alkaline reactor D. At this time, a 20 wt. % sodium hydroxide aqueous solution was added to give a concentration of sodium hydroxide of 0.1 wt. % relative to the charged liquid. The reaction temperature was maintained at 120° C. in the alkaline reactor D, and a reaction was performed at a residence time of 20 minutes.

A reaction crude liquid exiting the alkaline reactor D was then charged in the dealkalization column E. In the dealkalization column E, sodium hydroxide, a high boiling point substance, and a portion of 1,3-butylene glycol were discharged from the bottom of the column (corresponding to “X-5” in FIG. 1 ). The discharge amount from the bottom of the column was 5 parts relative to 100 parts of the charged liquid amount. On the other hand, from the top of the column were produced 95 parts of crude 1,3-butylene glycol (5) containing 1,3-butylene glycol and a low boiling point substance.

The crude 1,3-butylene glycol (5) was then charged in the product distillation column F. In the product distillation column F, 20 parts of a low boiling point substance and a portion of 1,3-butylene glycol relative to 100 parts of the charged liquid amount were distilled off from the top of the column (corresponding to “X-6” in FIG. 1 ), and the entire amount was discharged to the outside of the system. The operation was performed at a reflux ratio (reflux amount/distilled amount) of 1, and 80 parts of a 1,3-butylene glycol product was produced from the bottom of the column (corresponding to “Y” in FIG. 1 ).

As a result of the dry point and GC analysis for the above-described 1,3-butylene glycol product, the dry point was 208.9° C., the total area ratio of the impurity peaks longer in retention time (RT) than 1,3-butylene glycol was 0.6%, and the area ratio of the 1,3-butylene glycol peak was 99.1%. Furthermore, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 83%.

Example 2

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 1 except that the distilled amount from the top of the high boiling point component removal column C was changed to 85 parts. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 209.0° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 0.7%, and the area ratio of the 1,3-butylene glycol peak was 99.0%. Additionally, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 88%.

Example 3

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 1 except that the reflux ratio of the high boiling point component removal column C was changed to 0.2. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 208.7° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 0.2%, and the area ratio of the 1,3-butylene glycol peak was 99.5%. Furthermore, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 84%.

Example 4

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 1 except that the reflux ratio of the high boiling point component removal column C was changed to 0.6. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 208.6° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 0.05%, and the area ratio of the 1,3-butylene glycol peak was 99.7%. Furthermore, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 84%.

Example 5

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 1 except that the reflux ratio of the high boiling point component removal column C was changed to 0.6, and that the distilled amount from the top of the column was changed to 90 parts. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 208.7° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 0.2%, and the area ratio of the 1,3-butylene glycol peak was 99.5%. Furthermore, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 94%.

Example 6

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 1 except that the reflux ratio of the high boiling point component removal column C was changed to 1, and that the distilled amount form the top of the column was changed to 90 parts. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 208.6° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 0.1%, and the area ratio of the 1,3-butylene glycol peak was 99.6%. Furthermore, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 94%.

Example 7

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 1 except that the distilled amount from the top of the high boiling point component removal column C was 90 parts, that 5 parts of 10 parts of the bottom of the high boiling point component removal column C was discarded, that 5 parts thereof was recycled to the acetaldol production (aldol condensation of acetaldehyde), and that the reflux ratio of the high boiling point component removal column C was 1. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 208.7° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 0.2%, and the area ratio of the 1,3-butylene glycol peak was 99.5%. Furthermore, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 99% or greater.

Example 8

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 1 except that the distilled amount from the top of the high boiling point component removal column C was 90 parts, that 5 parts of 10 parts of the bottom of the high boiling point component removal column C was discarded, that 5 parts thereof was recycled to the acetaldol production, and that the reflux ratio of the high boiling point component removal column C was 10. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 208.7° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 0.1%, and the area ratio of the 1,3-butylene glycol peak was 99.6%. Furthermore, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 99% or greater.

Example 9

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 1 except that the distilled amount from the top of the high boiling point component removal column C was 90 parts, that 5 parts of the bottom of the high boiling point component removal column C was discarded, that 5 parts thereof was recycled to the acetaldol production, and that the reflux ratio was 20. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 208.6° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 0.08%, and the area ratio of the 1,3-butylene glycol peak was 99.6%. Furthermore, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 99% or greater.

Example 10

The procedure up to the dehydration was carried out in the same manner as in Example 1.

The crude 1,3-butylene glycol (2) produced from the bottom of the dehydration column A was charged in the desalting column B. In the desalting column B, a salt, a high boiling point substance, and a portion of 1,3-butylene glycol were discharged as the evaporation residue from the bottom of the column (corresponding to “X-3” in FIG. 1 ). The discharge amount of the evaporation residue was 10 parts relative to 100 parts of the charged liquid amount. On the other hand, from the top of the column, the crude 1,3-butylene glycol (3) containing 1,3-butylene glycol, a low boiling point substance, and a portion of a high boiling point substance was produced. As a result of the GC analysis of the crude 1,3-butylene glycol (3), the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 2%, and the area ratio of the 1,3-butylene glycol peak was 97%.

The crude 1,3-butylene glycol (3) was then charged in the high boiling point component removal column C. In the high boiling point component removal column C, a high boiling point substance and a portion of 1,3-butylene glycol were discharged from the bottom of the column (corresponding to “X-4” in FIG. 1 ). The discharge amount at the bottom of the column was 5 parts relative to 100 parts of the charged liquid amount, and the discharge was incinerated as it was. On the other hand, at the top of the column, 95 parts of crude 1,3-butylene glycol (4) containing a low boiling point substance was produced, as a distillate, in a reflux ratio (reflux amount/distilled amount) of 0.02.

Alkaline reaction, dealkalization, and product distillation were performed in the same manner as in Example 1 using this crude 1,3-butylene glycol (4). As a result of the dry point and GC analysis for the above-described 1,3-butylene glycol product produced from the bottom of the product distillation column, the dry point was 208.9° C., the total area ratio of the impurity peaks longer in retention time (RT) than 1,3-butylene glycol was 0.5%, and the area ratio of the 1,3-butylene glycol peak was 99.2%. Additionally, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 97%.

Example 11

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 10 except that the reflux ratio of the high boiling point component removal column C was 0.05. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 208.7° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 0.3%, and the area ratio of the 1,3-butylene glycol peak was 99.4%. Additionally, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 97%.

Example 12

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 10 except that the reflux ratio of the high boiling point component removal column C was 1. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 208.4° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 0.03%, and the area ratio of the 1,3-butylene glycol peak was 99.7%. Additionally, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 97%.

Example 13

The procedure up to the dehydration was carried out in the same manner as in Example 1.

The crude 1,3-butylene glycol (2) produced from the bottom of the dehydration column A was charged in the desalting column B. In the desalting column B, a salt, a high boiling point substance, and a portion of 1,3-butylene glycol were discharged as the evaporation residue from the bottom of the column (corresponding to “X-3” in FIG. 1 ). The discharge amount of the evaporation residue was 15 parts relative to 100 parts of the charged liquid amount. On the other hand, from the top of the column, the crude 1,3-butylene glycol (3) containing 1,3-butylene glycol, a low boiling point substance, and a portion of a high boiling point substance was produced. As a result of the GC analysis of the crude 1,3-butylene glycol (3), the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 0.5%, and the area ratio of the 1,3-butylene glycol peak was 99%.

The crude 1,3-butylene glycol (3) was then charged in the high boiling point component removal column C. In the high boiling point component removal column C, a high boiling point substance and a portion of 1,3-butylene glycol were discharged from the bottom of the column (corresponding to “X-4” in FIG. 1 ). The discharge amount at the bottom of the column was 5 parts relative to 100 parts of the charged liquid amount, and the discharge was incinerated as it was. On the other hand, at the top of the column, 95 parts of crude 1,3-butylene glycol (4) containing a low boiling point substance was produced, as a distillate, in a reflux ratio (reflux amount/distilled amount) of 0.02.

Alkaline reaction, dealkalization, and product distillation were performed in the same manner as in Example 1 using this crude 1,3-butylene glycol (4). As a result of the dry point and GC analysis for the above-described 1,3-butylene glycol product produced from the bottom of the product distillation column, the dry point was 208.6° C., the total area ratio of the impurity peaks longer in retention time (RT) than 1,3-butylene glycol was 0.2%, and the area ratio of the 1,3-butylene glycol peak was 99.7%. Additionally, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 95%.

Comparative Example 1

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 1 except that the reflux ratio of the high boiling point component removal column C was changed to 0.01, and that the reflux ratio of the product column was changed to 0.1. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 210.0° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 1.4%, and the area ratio of the 1,3-butylene glycol peak was 98.3%. Furthermore, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 83%.

Comparative Example 2

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 1 except that the reflux ratio of the high boiling point component removal column C was changed to 0.02, and that the reflux ratio of the product column was changed to 0.1. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 209.8° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 1.2%, and the area ratio of the 1,3-butylene glycol peak was 98.6%. Furthermore, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 83%.

Reference Example 1

A 1,3-butylene glycol product was produced from the bottom of the product column F by the same method as in Example 1 except that the reflux ratio of the high boiling point component removal column C was 0.02, that the reflux ratio of the product column was 0.1, and that the distilled amount from the top of the high boiling point component removal column C was 70 parts. As a result of the dry point and GC analysis for the 1,3-butylene glycol product, the dry point was 209.0° C., the total area ratio of the impurity peaks longer in retention time than 1,3-butylene glycol was 0.7%, and the area ratio of the 1,3-butylene glycol peak was 99.0%. Furthermore, the 1,3-butylene glycol recovery ratio at the high boiling point component removal column C was 73%.

Gas Chromatographic Analysis

A gas chromatographic analysis of the target 1,3-butylene glycol product was performed under the conditions below. A chromatogram of the gas chromatographic analysis of the 1,3-butylene glycol product in Example 10 is illustrated in FIG. 2 . In addition, a chromatogram of the gas chromatographic analysis of the 1,3-butylene glycol product in Comparative Example 2 is illustrated in FIG. 3 .

in which the conditions for the gas chromatographic analysis are as follows:

Analytical Instrument: Shimadzu GC 2010

Analytical Column: column with dimethylpolysiloxane as a stationary phase having a film thickness of 1.0 μm, a length of 30 m, and an inner diameter of 0.25 mm (Agilent J&W GC column—DB-1 available from Agilent Technologies Japan, Ltd.)

Heating conditions: heating from 80° C. to 120° C. at 5° C./min, then heating again to 160° C. at 2° C./min and maintaining for 2 minutes, and further heating to 230° C. at 10° C./min and maintaining at 230° C. for 18 minutes

Sample Introduction and Temperature: split sample introduction, 250° C.

Gas Flow Rate of Split and Carrier Gas: 23 mL/min, helium

Column Gas Flow Rate and Carrier Gas: 1 mL/min, helium

Detector and Temperature: a flame ionization detector (FID), 280° C.

Injection Sample: 0.2 μL of a 80 wt. % 1,3-butylene glycol product aqueous solution

[Measurement of Dry Point]

The test was conducted according to the test method specified in the normal pressure distillation test method of JIS K2254 “Petroleum products−distillation test method”.

Considerations of Results

The results of the above comparative examples, reference examples and examples are shown in Table 1.

TABLE 1 Comparative Comparative Reference Example Example Example Example Example Example 1 Example 2 Example 1 1 2 3 4 5 Charge Part 100 ← ← ← ← ← ← ← into high 1,3 BG GC 95 ← ← ← ← ← ← ← boiling area % point High boiling 3 ← ← ← ← ← ← ← component product GC removal area % column C High Reflux ratio* 0.01 0.02 0.02 0.05 0.05 0.2 0.6 0.6 boiling Distilled amount 80 80 70 80 80 80 80 90 point part component Amount of 20 20 30 20 15 20 20 10 removal bottom part** column C Recycled Absent Absent Absent Absent Absent Absent Absent Absent amount of bottom part 1,3 BG recovery 83 83 73 83 88 84 84 94 ratio % Bottom Part 80 80 80 80 80 80 80 80 (product) 1,3 BG GC 98.3 98.6 99 99.1 99 99.5 99.7 99.5 from area % product High boiling 1.4 1.2 0.7 0.6 0.7 0.2 0.05 0.2 column F product GC area % Dry point ° C. 210 209.8 209 208.9 209 208.7 208.6 208.7 *Reflux ratio = high boiling point component removal column reflux amount/high boiling point component removal column distilled amount **The numerical values put in parentheses in Examples 7 to 9 are discharge amounts to the outside of the system.

TABLE 2 Example Example Example Example Example Example Example Example 6 7 8 9 10 11 12 13 Charge into Part 100 ← ← ← 100 ← ← 100 high boiling 1,3 BG GC area % 95 ← ← ← 97 ← ← 99 point High boiling product 3 ← ← ← 2 ← ← 0.5 component GC area % removal column C High Reflux ratio* 1 1 10 20 0.02 0.05 1 0.02 boiling Distilled amount part 90 90 90 90 95 95 95 95 point Amount of bottom 10 10(5) 10(5) 10(5) 5 5 5 5 component part** removal Recycled amount of Absent 5 5 5 Absent Absent Absent Absent column C bottom part 1,3 BG recovery 94 99 or 99 or 99 or 97 97 97 95 ratio % greater greater greater Bottom Part 80 80 80 80 80 80 80 80 (product) 1,3 BG GC area % 99.6 99.5 99.6 99.6 99.2 99.4 99.7 99.7 from High boiling product 0.1 0.2 0.1 0.08 0.5 0.3 0.03 0.2 product GC area % column F Dry point ° C. 208.6 208.7 208.7 208.6 209 208.7 208.4 208.6 *Reflux ratio = high boiling point component removal column reflux amount/high boiling point component removal column distilled amount **The numerical values put in parentheses in Examples 7 to 9 are discharge amounts to the outside of the system.

From Comparative Examples 1 and 2, in the case where the 1,3 BG purity in charged liquid into the high boiling point component removal column C was 95 GC area %, when the distilled amount was 20 parts relative to 100 parts of the charged liquid into the high boiling point component removal column C, the effect of removing the high boiling point substance was low and the product dry point was not satisfactory, even though the reflux ratio was 0.02. As illustrated in Reference Example 1, when the distilled amount was 30 parts with respect to 100 parts of the charged liquid in the high boiling point component removal column C, the reflux ratio was 0.02, and the dry point satisfied 209° C. or lower. However, the 1,3 BG recovery ratio in the high boiling point component removal column C was very bad, i.e., 73%. Thus, this was economically disadvantageous.

From Comparative Examples 1 and 2 and Examples 1, 3, and 4, it can be understood that, when the reflux ratio of the high boiling point component removal column was increased to 0.05 or greater, it was possible to further concentrate and remove the high boiling impurities in the high boiling point component removal column C, that the GC purity of the product was improved, and that the dry point of the product was 209° C. or lower, which was not higher than the standard value (quasi-drug raw material standard).

It can be seen that the 1,3 BG recovery ratio can be improved by reducing the bottom ratio (the bottom cut ratio) of the high boiling point component removal column C, from Examples 1 and 2 and Examples 4 to 6. Therefore, when the bottom ratio was reduced, the high boiling impurities that could be removed decreased, the high boiling impurities in the product increased, and thus the dry point lowered. Therefore, the product dry point needs to be adjusted to 209° C. or lower.

According to Examples 6 and 7, when a portion of the bottom of the high boiling point component removal column C was recycled to the acetaldehyde polymerization (acetaldol production by dimerization of acetaldehyde), the high boiling impurities were decomposed and/or removed. Therefore, the 1,3 BG recovery ratio was greatly improved, while the decrease in product purity and the increase in dry point could be suppressed to the minimum.

It can be seen that, in Examples 7 to 9, even when the reflux ratio of the high boiling point component removal column C was increased to a certain value or greater, the product quality was not improved any more. According to Comparative Example 2, Reference Example 1, and Examples 10 and 13, either the amount of the bottom extracted from the high boiling point component removal column C was increased or the 1,3 BG purity of the charged liquid into the high boiling point component removal column C was increased, and the quality of the 1,3 BG product was sufficiently improved even when the reflux ratio was somewhat small. The quality of the 1,3 BG product (purity, dry point, etc.) was improved by increasing the reflux ratio of the high boiling point component removal column C, according to Examples 10 to 12.

Example 13 was a case in which the concentration of 1,3 BG in the charged liquid in the high boiling point component removal column was greater than that in Examples 1 and 10. It can be seen that, when the 1,3 BG concentration was high and the high boiling point impurity concentration was low, a good product was produced even with a small reflux ratio of the high boiling point component removal column.

Note that, among 1,3-butylene glycol products produced by known methods, there was no high-quality product having a dry point of 209° C. or lower, a purity (GC area %) of 1,3-butylene glycol of greater than 98.5%, and a content of the high boiling point substance (GC area %) of less than 1.2%.

As a summary of the above, configurations and variations of the present disclosure are described below.

[1] A method for producing 1,3-butylene glycol to yield purified 1,3-butylene glycol from a reaction crude liquid containing 1,3-butylene glycol,

the method including: performing dehydration including removing water by distillation, removing high boiling point component including removing a high boiling point component by distillation, and performing product distillation to yield purified 1,3-butylene glycol,

wherein, in a high boiling point component removal column for use in the removing the high boiling point component, a charged liquid containing 1,3-butylene glycol is distilled under a condition that a reflux ratio is greater than 0.02 (or 0.025 or greater, 0.05 or greater, 0.1 or greater, 0.2 or greater, 0.3 or greater, 0.4 or greater, 0.5 or greater, 0.6 or greater, 0.7 or greater, 0.8 or greater, 0.9 or greater, 1 or greater, 1.2 or greater, 1.5 or greater, 2 or greater, 3 or greater, 4 or greater, 5 or greater, 10 or greater, or 20 or greater) in a case where a concentration of 1,3-butylene glycol in the charged liquid is 95% or less, or a reflux ratio is greater than 0.01 (or 0.015 or greater, 0.05 or greater, 0.1 or greater, 0.2 or greater, 0.3 or greater, 0.4 or greater, 0.5 or greater, 0.6 or greater, 0.7 or greater, 0.8 or greater, 0.9 or greater, 1 or greater, 1.2 or greater, 1.5 or greater, 2 or greater, 3 or greater, 4 or greater, 5 or greater, 10 or greater, or 20 or greater) in a case where the concentration of 1,3-butylene glycol in the charged liquid is greater than 95%, high-purity 1,3-butylene glycol is distilled off from above a charging plate, and a liquid in which a high boiling point component is concentrated is extracted from below the charging plate.

[2] The method for producing 1,3-butylene glycol according to [1], wherein an upper limit of the reflux ratio is 100 (or 50).

[3] The method for producing 1,3-butylene glycol according to [1] or [2], wherein the reaction crude liquid containing 1,3-butylene glycol is a reaction crude liquid produced by hydrogen reduction of acetaldols (or a reaction crude liquid produced by hydrolysis of 1,3-butylene oxide, a reaction crude liquid produced by selective hydrocracking of erythritol, a reaction crude liquid produced by selective hydration to butadiene, a reaction crude liquid produced by hydrogen addition to n-butanal-3-one, a reaction crude liquid produced by hydrogen addition to 1-butanol-3-one, a reaction crude liquid produced by hydrogen addition to 3-hydroxy-l-butanoic acid, a reaction crude liquid produced by hydrogen addition to β-butyrolactone, or a reaction crude liquid produced by hydrogen addition to diketene.

[4] The method for producing 1,3-butylene glycol according to [3], wherein the acetaldols used as a raw material in reduction (hydrogenation) of the acetaldols is any of acetaldol; its cyclic dimer paraldol; aldoxane as a cyclic trimer of acetaldehyde; and mixtures of these.

[5] The method for producing 1,3-butylene glycol according to [4], wherein the acetaldols is produced by an aldol condensation reaction of acetaldehyde in the presence of a basic catalyst or produced by pyrolysis of aldoxane.

[6] The method for producing 1,3-butylene glycol according to any one of [3] to [5], wherein the reaction crude liquid containing the acetaldols is neutralized with an acid and used in the production of 1,3-butylene glycol.

[7] The method for producing 1,3-butylene glycol according to any one of [3] to [6], wherein the reaction crude liquid containing the acetaldols is subjected to simple evaporation, distillation, or hydrogen addition to remove aldehydes, followed by the hydrogenation.

[8] The method for producing 1,3-butylene glycol according to any one of [3] to [7], wherein a content of the acetaldols used as the raw material in reduction (hydrogenation) of the acetaldols is 30 wt. % or greater (e.g., from 30 to 99 wt. %) (or 40 wt. % or greater (e.g., from 40 to 98 wt. %), 50 wt. % or greater (e.g., from 50 to 97 wt. %), 60 wt. % or greater (e.g., from 60 to 95 wt. %), from 65 to 90 wt. %, from 70 to 90 wt. %, or 75 to 90 wt. %).

[9] The method for producing 1,3-butylene glycol according to any one of [3] to [8], wherein the raw material for reduction (hydrogenation) of the acetaldols contains water, and a content of the water is 2 wt. % or greater (or 5 wt. % or greater, 10 wt. % or greater, or 15 wt. % or greater), an upper limit of the water content is 90 wt. % (or 80 wt. %, 70 wt. %, 60 wt. %, 50 wt. %, 40 wt. %, 30 wt. %, or 20 wt. %).

[10] The method for producing 1,3-butylene glycol according to any one of [3] to [9], wherein an amount of a hydrogenation catalyst for reduction (hydrogenation) of the acetaldols is from 1 to 30 parts by weight (or from 4 to 25 parts by weight, from 8 to 20 parts by weight, or from 12 to 18 parts by weight) relative to 100 parts by weight of a raw material for hydrogenation.

[11] The method for producing 1,3-butylene glycol according to any one of [3] to [10], wherein an amount of hydrogen used in a reduction (hydrogenation) reaction of the acetaldols is from 0.5 to 40 parts by weight (or from 1 to 30 parts by weight, from 4 to 20 parts by weight, or from 8 to 12 parts by weight) relative to 100 parts by weight of the raw material for hydrogenation.

[12] The method for producing 1,3-butylene glycol according to any one of [3] to [11], wherein a pressure (total pressure, gauge pressure) in a reaction system in the reduction (hydrogenation) reaction of the acetaldols is from 9 to 70 MPa (or from 10 to 40 MPa).

[13] The method for producing 1,3-butylene glycol according to any one of [3] to [12], wherein a hydrogen pressure (partial pressure of hydrogen) in the reaction system in the reduction (hydrogenation) reaction of the acetaldols is from 7 to 60 MPa (or 10 to 30 MPa).

[14] The method for producing 1,3-butylene glycol according to any one of [3] to [13], wherein a reaction temperature in the reduction (hydrogenation) reaction of the acetaldols is from 40 to 150° C. (or from 50 to 140° C., or from 60 to 130° C.).

[15] The method for producing 1,3-butylene glycol according to any one of [4] to [14], wherein a reaction time (residence time) in the reduction (hydrogenation) reaction of the acetaldols is from 10 to 500 minutes (or from 20 to 400 minutes, from 30 to 300 minutes, from 50 to 280 minutes, or from 80 to 250 minutes).

[16] The method for producing 1,3-butylene glycol according to any one of [1] to [15], further including dealcoholization including removing a low boiling point component containing an alcohol in a process stream containing 1,3-butylene glycol.

[17] The method for producing 1,3-butylene glycol according to any one of [1] to [16], further including desalting including removing a salt in the process stream containing 1,3-butylene glycol.

[18] The method for producing 1,3-butylene glycol according to [17], wherein a bottom ratio (%) in the desalting [(desalting column bottom amount (part)/desalting column charged amount (part)·100] is from 0.1 to 40 wt. % (or from 1 to 35 wt. %, from 2 to 30 wt. %, from 3 to 25 wt. %, from 5 to 20 wt. %, or from 7 to 15 wt. %).

[19] The method for producing 1,3-butylene glycol according to any one of [1] to [18], wherein the high boiling point component removal column is a packed column (or perforated-plate column or a bubble column), and a reboiler employed is a natural downward flow thin-film evaporator or a forced-stirring thin-film evaporator.

[20] The method for producing 1,3-butylene glycol according to any one of [1] to [19], wherein a reflux ratio of the high boiling point component removal column is greater than 0.02.

[21] The method for producing 1,3-butylene glycol according to any one of [1] to [20], wherein a concentration of 1,3-butylene glycol in the charged liquid into the high boiling point component removal column is 95% or greater (or 96% or greater, 97% or greater, 98% or greater, or 99% or greater).

[22] The method for producing 1,3-butylene glycol according to any one of [1] to [21], wherein a content of the high boiling point component in the charged liquid into the high boiling point component removal column is 4% or less (or 3% or less, 2% or less, 1% or less, 0.5% or less, 0.4% or less, 0.3% or less, or 0.2% or less).

[23] The method for producing 1,3-butylene glycol according to any one of [1] to [22], wherein a content of the high boiling point component in the charged liquid into the high boiling point component removal column is 0.1% or less (or 0.05% or less, or 0.01% or less).

[24] The method for producing 1,3-butylene glycol according to any one of [1] to [23], wherein a bottom ratio in the high boiling point component removal column is less than 30 wt. % (or 25 wt. % or less, 20 wt. % or less, 15 wt. % or less, 10 wt. % or less, 7 wt. % or less, 5 wt. % or less, 4 wt. % or less, 3 wt. % or less, 2 wt. % or less, or 1 wt. % or less).

[25] The method for producing 1,3-butylene glycol according to any one of [1] to [24], wherein a bottom ratio in the high boiling point component removal column is 0.01 wt. % or greater (or 0.1 wt. % or greater, 0.5 wt. % or greater, 1 wt. % or greater, 2 wt. % or greater, 3 wt. % or greater, 4 wt. % or greater, 5 wt. % or greater, 6 wt. % or greater, 7 wt. % or greater, 8 wt. % or greater, 9 wt. % or greater, 10 wt. % or greater, 15 wt. % or greater, or 20 wt. % or greater).

[26] The method for producing 1,3-butylene glycol according to any one of the above [1] to [25], wherein a theoretical number of plates of the high boiling point component removal column is from 1 to 100 plates (or from 2 to 90 plates, from 3 to 80 plates, from 4 to 70 plates, from 5 to 60 plates, from 8 to 50 plates, from 10 to 40 plates, or from 15 to 30 plates).

[27] The method for producing 1,3-butylene glycol according to any one of [1] to [26], wherein a feed position of the charged liquid is from 10 to 90% (or from 20 to 80%, from 30 to 70%, or from 40 to 60%) of a height of the column downward from the top of the high boiling point component removal column.

[28] The method for producing 1,3-butylene glycol according to any one of [1] to [27], wherein, in the distillation in the high boiling point component removal column, a pressure (absolute pressure) at the top of the column is from 0.01 to 50 kPa (or from 0.1 to 30 kPa, or from 0.3 to 20 kPa, or from 0.5 to 10 kPa).

[29] The method for producing 1,3-butylene glycol according to any one of the items [1] to [28], wherein at least a portion of the bottom from the high boiling point component removal column is recycled to the step prior to the removing a high boiling point component.

[30] The method for producing 1,3-butylene glycol according to [29], wherein the step prior to the removing a high boiling point component is an acetaldehyde polymerization (or reaction (hydrogenation), dealcoholization (low boiling point component removal), dehydration, or desalting).

[31] The method for producing 1,3-butylene glycol according to [29] or [30], wherein a recycled amount of the bottom in the high boiling point component removal column recycled to the step prior to the removing a high boiling point component is, in a range not greater than an amount of the bottom in the high boiling point component removal column, less than 30 wt. % (or 25 wt. % or less, 20 wt. % or less, 15 wt. % or less, 10 wt. % or less, 7 wt. % or less, 5 wt. % or less, 4 wt. % or less, 3 wt. % or less, 2 wt. % or less, or 1 wt. % or less), with respect to a charged amount into the high boiling point component removal column.

[32] The method for producing 1,3-butylene glycol according to any one of [29] to [31], wherein the recycled amount of the bottom in the high boiling point component removal column recycled to the step prior to the removing a high boiling point component is, in a range not greater than an amount of the bottom in the high boiling point component removal column, 0.01 wt. % or greater (or 0.1 wt. % or greater, 2 wt. % or greater, 3 wt. % or greater, 4 wt. % or greater, 5 wt. % or greater, 7 wt. % or greater, 10 wt. % or greater, or 20 wt. % or greater), with respect to the charged amount into the high boiling point component removal column.

[33] The method for producing 1,3-butylene glycol according to any one of [1] to [32], further including performing alkaline treatment including treating a process stream comprising 1,3-butylene glycol with a base.

[34] The method for producing 1,3-butylene glycol according to [33], wherein the base is added in an amount of from 0.05 to 10 wt. % (or from 0.1 to 1.0 wt. %) relative to a crude 1,3-butylene glycol stream subjected to the alkaline treatment.

[35] The method for producing 1,3-butylene glycol according to [34], wherein the base added in the alkaline treatment is an alkali metal compound.

[36] The method for producing 1,3-butylene glycol according to [35], wherein the alkali metal compound is sodium hydroxide (or potassium hydroxide, sodium (bi)carbonate, or potassium (bi)carbonate).

[37] The method for producing 1,3-butylene glycol according to any one of [33] to [36], wherein a reaction temperature of the alkaline treatment is from 90 to 140° C. (or from 110 to 130° C.), and a reaction residence time is from 5 to 120 minutes (or from 10 to 30 minutes).

[38] The method for producing 1,3-butylene glycol according to any one of [33] to [37], wherein evaporation is performed in an evaporator used in the alkaline treatment under a reduced pressure at the top of the column of 20 kPa or less (absolute pressure) (or from 0.5 to 10 kPa (absolute pressure)) at from 90 to 120° C.

[39] The method for producing 1,3-butylene glycol according to any one of [1] to [38], wherein the product distillation column used in the product distillation is a packed column (or perforated-plate column or a bubble column), and a reboiler employed is a natural downward flow thin-film evaporator or a forced-stirring thin-film evaporator.

[40] The method for producing 1,3-butylene glycol according to [39], wherein a theoretical number of plates of the product distillation column is from 1 to 100 plates (or from 2 to 90 steps, from 3 to 80 plates, from 4 to 70 plates, from 5 to 60 plates, from 8 to 50 plates, from 10 to 40 plates, or from 15 to 30 plates), in a case where the concentration of the low boiling point substance in the charged liquid is 5 wt. % or less.

[41] The method for producing 1,3-butylene glycol according to [39] or [40], wherein a feed position of the charged liquid in the product distillation column is from 10 to 90% (or from 20 to 80%, from 30 to 70%, from 40 to 60%) of a height of the column downward from the top of the column, and a pressure (absolute pressure) at the top of the column is from 20 kPa or less (or from 0.1 to 10 kPa, from 0.3 to 8 kPa, or from 0.5 to 5 kPa).

[42] The method for producing 1,3-butylene glycol according to any one of [39] to [41], wherein a reflux ratio in the product distillation column is from 0.05 to 500 (or from 0.1 to 300, from 0.2 to 200, from 0.5 to 100, from 1 to 50, from 2 to 40, from 3 to 30, or from 4 to 25).

[43] A 1,3-butylene glycol product, having a dry point of 209° C. or lower and, according to a gas chromatographic analysis performed under conditions set forth below:

an area ratio of a 1,3-butylene glycol peak of greater than 98.5% (or 98.6% or greater, 98.7% or greater, 98.8% or greater, 98.9% or greater, 99% or greater, 99.1% or greater, 99.2% or greater, 99.3%, 99.4% or greater, 99.5% or greater, 99.6% or greater, or 99.7% or greater) and a total area ratio of peaks longer in retention time than the 1,3-butylene glycol peak of less than 1.2% (or 1.1% or less, 1% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, 0.1% or less, 0.05% or less, or 0.03% or less),

in which the conditions for the gas chromatographic analysis are as follows:

Analytical Column: a column with dimethylpolysiloxane as a stationary phase, having a length of 30 m, an inner diameter of 0.25 mm, and a film thickness of 1.0 μm

Heating conditions: heating from 80° C. to 120° C. at 5° C./min, then heating again to 160° C. at 2° C./min and maintaining for 2 minutes, and further heating to 230° C. at 10° C./min and maintaining at 230° C. for 18 minutes

Sample Introduction Temperature: 250° C.

Carrier Gas: helium

Column Gas Flow Rate: 1 mL/min

Detector and Detection Temperature: a flame ionization detector (FID), 280° C.

[44] The 1,3-butylene glycol product according to [43], wherein the area ratio of the 1,3-butylene glycol peak is 99.0% or greater.

[45] The 1,3-butylene glycol product according to [43] or [44], wherein the total area ratio of the peaks longer in retention time than the 1,3-butylene glycol peak is 0.6% or less.

[46] A moisturizer containing the 1,3-butylene glycol product described in any one of [43] to [45].

[47] A cosmetic product containing the moisturizer described in [46].

INDUSTRIAL APPLICABILITY

With the 1,3-butylene glycol product according to the present disclosure, high-purity 1,3-butylene glycol having a very low content of a high boiling point component and a low dry point can be produced with a high recovery ratio. This 1,3-butylene glycol product has excellent moisturizing performance and can be used as a raw material for a moisturizer and a cosmetic product that can retain high quality for a long period of time.

REFERENCE SIGNS LIST

-   A: Dehydration column -   B: Desalting column -   C: Distillation column for removing high boiling point substance     (high boiling point component removal column) -   D: Alkaline reactor -   E: Dealkalization column -   F: Product distillation column -   A-1, B-1, C-1, E-1, F-1: Condenser -   A-2, C-2, F-2: Reboiler -   X-1: Crude 1,3-butylene glycol -   X-2: Water (discharged water) -   X-3: A salt, a high boiling point substance, and a portion of     1,3-butylene glycol -   X-4: A high boiling point substance and a portion of 1,3-butylene     glycol -   X-5: Sodium hydroxide, a high boiling point substance, and a portion     of 1,3-butylene glycol -   X-6: A low boiling point substance and a portion of 1,3-butylene     glycol -   Y: 1,3-butylene glycol product 

1. A method for producing 1,3-butylene glycol to yield purified 1,3-butylene glycol from a reaction crude liquid including 1,3-butylene glycol, the method comprising: performing dehydration including removing water by distillation; removing a high boiling point component including removing a high boiling point component by distillation; and performing product distillation to yield purified 1,3-butylene glycol, wherein, in a high boiling point component removal column for use in the removing the high boiling point component, a charged liquid including 1,3-butylene glycol is distilled under a condition that a reflux ratio is greater than 0.02 in a case where a concentration of 1,3-butylene glycol in the charged liquid is 95% or less, or a reflux ratio is greater than 0.01 in a case where a concentration of 1,3-butylene glycol in the charged liquid is greater than 95%, and high-purity 1,3-butylene glycol is distilled off from above a charging plate, and a liquid in which a high boiling point component is concentrated is extracted from below the charging plate.
 2. The method for producing 1,3-butylene glycol according to claim 1, wherein the reaction crude liquid including 1,3-butylene glycol is a reaction crude liquid yielded by hydrogen reduction of acetaldols.
 3. The method for producing 1,3-butylene glycol according to claim 1, further comprising performing alkaline treatment including treating a process stream including 1,3-butylene glycol with a base.
 4. The method for producing 1,3-butylene glycol according to claim 1, further comprising performing desalting including removing a salt in the process stream including 1,3-butylene glycol.
 5. The method for producing 1,3-butylene glycol according to claim 1, further comprising performing dealcoholization including removing a low boiling point component including an alcohol, the low boiling point component being present in the process stream including 1,3-butylene glycol.
 6. The method for producing 1,3-butylene glycol according to claim 1, wherein the reflux ratio of the high boiling point component removal column is greater than 0.02.
 7. The method for producing 1,3-butylene glycol according to claim 1, wherein the concentration of 1,3-butylene glycol in the charged liquid into the high boiling point component removal column is 95% or greater.
 8. The method for producing 1,3-butylene glycol according to claim 1, wherein a content of the high boiling point component in charged liquid into the high boiling point component removal column is 4% or less.
 9. The method for producing 1,3-butylene glycol according to claim 1, wherein the content of the high boiling point component in charged liquid into the high boiling point component removal column is 0.1% or less.
 10. The method for producing 1,3-butylene glycol according to claim 1, wherein a bottom ratio in the high boiling point component removal column is less than 30 wt. %.
 11. The method for producing 1,3-butylene glycol according to claim 1, wherein the bottom ratio in the high boiling point component removal column is 0.01 wt. % or greater.
 12. The method for producing 1,3-butylene glycol according to claim 1, wherein a theoretical number of plates in the high boiling point component removal column is from 1 to 100 plates.
 13. The method for producing 1,3-butylene glycol according to claim 1, wherein at least a portion of a bottom from the high boiling point component removal column is recycled to a step prior to the removing the high boiling point component.
 14. The method for producing 1,3-butylene glycol according to claim 13, wherein a recycled amount of the bottom from the high boiling point component removal column recycled to the step prior to the removing the high boiling point component is less than 30 wt. % with respect to a charged amount into the high boiling point component removal column, in a range not greater than an amount of the bottom from the high boiling point component removal column.
 15. The method for producing 1,3-butylene glycol according to claim 13, wherein a recycled amount of the bottom from the high boiling point component removal column recycled to the step prior to the removing the high boiling point component is 0.01 wt. % or greater with respect to a charged amount into the high boiling point component removal column, in a range not greater than an amount of the bottom from the high boiling point component removal column.
 16. A 1,3-butylene glycol product, having a dry point of 209° C. or lower and, in a gas chromatographic analysis, an area ratio of a 1,3-butylene glycol peak of greater than 98.5% and a total area ratio of peaks longer in retention time than the 1,3-butylene glycol peak of less than 1.2%, wherein the gas chromatographic analysis is conducted under conditions in which an analytical column is a column with dimethylpolysiloxane as a stationary phase, having a film thickness of 1.0 μm, a length of 30 m, and an inner diameter of 0.25 mm; heating conditions include heating from 80° C. to 120° C. at 5° C./min, then heating again to 160° C. at 2° C./min and maintaining for 2 minutes, and further heating to 230° C. at 10° C./min and maintaining at 230° C. for 18 minute; a sample introduction temperature is 250° C.; a carrier gas is helium, a column gas flow rate is 1 mL/min, and a detector and detection temperature are a flame ionization detector (FID) and 280° C., respectively.
 17. The 1,3-butylene glycol product according to claim 16, wherein the area ratio of the 1,3-butylene glycol peak is 99.0% or greater.
 18. The 1,3-butylene glycol product according to claim 16, wherein the total area ratio of the peaks longer in retention time than the 1,3-butylene glycol peak is 0.6% or less.
 19. A moisturizer comprising the 1,3-butylene glycol product described in claim
 16. 20. A cosmetic product comprising the moisturizer described in claim
 19. 